1. ## Drawing curves on a road.

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I read a few threads on splines, plines and arcs, but still can't get the results I'm looking for. I'm trying to draw a road with known dimensions. How do I draw the curves? Do I use spline, pline or arc?

2. Unless you need a spiral, draw 2 tangents (lines or plines) and use the fillet command for the correct radius.

3. How would you draw the curves if you were doing it on a drafting board instead of using CAD? Since you should have all the curve data it should be a no brainer.

4. I'm trying to recreate a roadway drawing that was given to me. All I had to do was put boring symbols over the drawing. I've never used a drafting board and I'm teaching myself CAD. I'm just using this drawing with dimensions on it as an exercise to get more familiar with the tools and commands. I tried using the fillet command, and it gives me close to what I want, but it starts the tangent about 200' too soon. I'll have to move every curve that I make over to the right.

I basically have a stretch of road that is 900' long and goes into a curve approx. 600' long with a radius of 858.75'.

5. Learning curve geometry would help you draw this. To get curve to start at the end of the line, offset the centerline by the radius (858.75'), use the end of the offset line to draw a circle. Trim circle to create centerline curve. Adjust length with "lengthen" command.

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I agree with CarlB about learning horizontal curve geometry.

The curve "starts" at what is called the PC or point of curvature and ends at the PT or point of tangency. You'll need to know the delta or angle of the curve and the radius. You can compute the tangent distance, curve length and chord distance if it hasn't been supplied.